Research into reproduction will be carried out to understand the reproductive process in order to ultimately control it. The proposed research will deal with biochemistry and physiology of uterine smooth muscle. Uterine contractility will be studied in a 3-pronged attack on the subcellular level: 1) The contractile proteins, 2) sarcoplasmic reticulum calcium-binding, 3) hormonal regulation of calcium transport. METHODS: 1) A calcium-binding protein will be isolated from sarcoplasmic reticulum preparations, purified and characterized. 2) Calcium binding of uterine sarcoplasmic reticulum from pregnant animals and humans will be studied using atomic absorption spectrocospy or millipore filtration. 3) Effects of hormones and pharmacological agents on calcium binding of uterine SR will be evaluated. BIBLIOGRAPHIC REFERENCES: Carsten, Mary E.: On the mode of action of prostaglandins in myometrial activation, Gynecol. Invest. 6:34, 1975. Carsten, M.E.: Calcium transport in the myometrium and its regulation by hormones, abstract of the Symposium on The Biochemistry of Smooth Muscle, University of Manitoba, Aug. 1975.